Main Entry:  de·lu·sion  Pronunciation:  \di-ˈlü-zhən, dē-\ Function:  noun Etymology:  Middle English, from Late Latin delusion-, delusio, from deludere Date:  15th century 1: the act of deluding : the state of being deluded2 a: something that is falsely or delusively believed or propagated b: a persistent false psychotic belief regarding the self or persons or objects … More Word Of The Day: Delusional